What to pack for Cancún: the no-regret list

Bottom line: Cancún is warm every day of the year, the plugs are the same as home, and every resort sells sunscreen at three times the price you would pay at a pharmacy. Pack light on clothes and heavy on the things that are expensive or hard to find there: reef-safe sunscreen, a dry bag, water shoes, a good hat, your own snorkel mask and a stash of small peso notes. The rest of this list is about matching the bag to the trip and the month.

The ten things people regret not bringing

Reef-safe, biodegradable sunscreen. Cenotes, Xcaret-style parks and most snorkel boats require it, and on-site prices are steep. Bring two bottles.
Water shoes. Cenote ladders, rocky entries at Akumal and Puerto Morelos, and the hot sand at midday. Cheap ones are fine.
A dry bag. Boat days, cenote days, afternoon storms June–October. A 10-litre roll-top holds a phone, a wallet and a shirt.
Your own snorkel mask. Rental masks leak and tour boats have a limited size range. Fins can be borrowed; a mask that fits your face cannot.
Small peso notes. Tips run MXN 20–50 a drink round or bag, MXN 10–20 for gas attendants and grocery baggers, and nobody has change for a 500. Get pesos from a bank ATM on arrival, then break them at a supermarket.
A wide-brim hat with a chin strap. Ballcaps lose on a catamaran. Boat days are where the worst burns happen.
Insect repellent. Mosquitoes are year-round and worst June–October, at cenotes, on the Tulum beach road and near the lagoon.
A light long-sleeve layer. A norte front in December–February brings a grey, windy day; ADO buses and restaurants run the air conditioning hard; and a rash guard beats reapplying sunscreen on a snorkel tour.
A copy of your passport and confirmations, offline. Your entry stamp is your permit — there is no paper FMM any more — so photograph the stamped page too. Screenshot transfer confirmations; airport Wi-Fi is not something to rely on.
Cash for the VISITAX, done from home. Not a physical item, but a pre-trip task people forget: about MXN 270 (~US$15) per person, any age, on the official Quintana Roo site only. The look-alike sites charge multiples.

What each trip type needs

Trip type	The base list	Add these
Resort week in the Hotel Zone or Puerto Morelos	Swimwear ×3, cover-up, sandals, one dinner outfit per two nights, sunscreen, hat	Insulated cup for the pool, reef shoes for the rocky bits, small bills for staff, a resort-dress-code outfit (many à la carte restaurants want long trousers and closed shoes for men)
Excursion-heavy: Chichén Itzá, cenotes, Sian Ka'an	Everything above plus trainers or trail sandals	Dry bag, water shoes, own mask, refillable bottle, cash for tolls and site entries, a daypack that fits under a bus seat, repellent, a change of clothes for the ride home
Couples and honeymoons	Resort list	One genuinely nice outfit each for a Playa or Tulum dinner, something for a sunset cruise, a portable speaker for the balcony, reef-safe sunscreen that does not stain white linen
Family with kids	Resort list, doubled for the under-tens	Kids' rash guards and swim shirts, a puddle-jumper float, kids' reef-safe sunscreen, a small first-aid kit with rehydration sachets, snacks for the transfer, a car seat if you are booking a private transfer and want your own
Isla Mujeres or Cozumel base	Resort list minus the dress-code outfit	Water shoes for the reef, a mask you trust, a dry bag for the ferry and golf cart, a lightweight rain shell for the crossing

Two notes on that table. The dress-code line matters more than people expect: resort à la carte restaurants routinely turn men away in shorts and flip-flops at dinner. And the "own mask" advice is doubled for Cozumel, where the diving and snorkelling is the whole point and the rental gear on the cattle boats is not.

By month

Cancún does not really have a cold season, but it has three distinct packing seasons.

December to April (dry, high season). Highs in the low-to-mid 80s, low humidity, the Caribbean at its clearest. Pack the base list and one long-sleeve layer: January and December bring the occasional norte cold front — a grey, windy day where a light jacket at dinner is welcome. Sargassum is minimal until it starts creeping in on east-facing beaches in April, so a beach in front of your resort is likely to be usable all winter. March is spring-break season in the Hotel Zone and on Playa's Quinta; if that is you, add earplugs. If it is not you, our March guide covers where to hide.

May to August (hot, wet, sargassum). Highs push 89–91°F with real humidity, afternoon storms arrive and the water sits at bath temperature. Pack lighter fabrics than you think you need, twice as much sunscreen, a compact umbrella or rain shell for the 20-minute downpours, repellent, and water shoes for the seaweed. Whale sharks run June through mid-August off Isla Mujeres — a rash guard and your own mask make the whale shark swim far more pleasant. The cenotes feel like air conditioning in July; bring the water shoes.

September to November (hurricane season, then the switch). September and October are the cheapest, emptiest months and the ones that want travel insurance and a flexible bag: a rain shell, a dry bag, a second pair of shoes that can get soaked, and a book for a rained-out afternoon. By mid-November the dry season arrives, humidity drops and sargassum clears; a late-November trip packs like a December one. Check the month-by-month guide for the specific week you are looking at, because the difference between October 5 and October 25 is significant.

Documents, money and tech

Documents: a passport valid for the stay (no visa for U.S. or Canadian citizens; the officer stamps the days granted, up to 180 — check it), a printed or screenshotted VISITAX receipt, transfer and tour confirmations, travel insurance details, and a photo of everything on your phone. Kids need their own passports. Bring the rental-car voucher and a credit card in the driver's name if you are renting.

Money: pesos, from a bank ATM (Banorte, BBVA, Santander), never a standalone Hotel Zone machine. Decline dynamic currency conversion at every terminal. Dollars are accepted at resorts and in the Hotel Zone at a poor rate, so bring a few small U.S. bills as a backup and nothing more. A card with no foreign transaction fee, and a second card kept in the room safe. Community advice is to sort your currency at your home bank if you want to land with cash; otherwise the arrivals-hall bank ATM is fine.

Tech: no adapter needed — outlets are the standard North American type. A power bank for boat and ruin days. An eSIM or a Mexican SIM if you plan to leave the resort; resort Wi-Fi covers the rest. Download offline maps for the Riviera Maya and screenshot your routes if you are driving, because signal drops on the road to the cenotes.

What not to pack, and what to buy there

Leave at home: a full-size hair dryer (every resort has one), a plug adapter, more than one pair of jeans, a heavy raincoat, hiking boots (trainers handle Chichén Itzá and Tulum fine), and a beach towel (resorts provide them; only pack one for a hostel stay).

Buy there: bottled water, snacks, basic toiletries, a cheap cooler bag, flip-flops if yours break, and any medication you forgot — pharmacies are on every corner and many have a doctor on site. Sunscreen and repellent are available everywhere but at a premium, and the reef-safe formulations the parks require are the hardest to find at a fair price, which is why they lead this list.

The copy-paste checklist

Documents and money

Passport (valid for the stay); photo of the stamped page after arrival
VISITAX receipt (official site only, ~MXN 270 per person)
Transfer, tour and resort confirmations, offline
Travel insurance card and policy number
No-foreign-fee credit card plus a backup card
Small U.S. bills as backup; pesos from a bank ATM on arrival

Sun and water

Reef-safe, biodegradable sunscreen ×2
Wide-brim hat with strap; sunglasses with a strap
Rash guard or long-sleeve swim shirt
Own snorkel mask; water shoes
10-litre dry bag; refillable bottle
After-sun and lip balm with SPF

Clothes

Swimwear ×3; cover-up; sandals; trainers
Light shorts, tees, one or two linen or breathable shirts
One dinner outfit per two nights; long trousers and closed shoes for men
One light long-sleeve layer (nortes, air conditioning, buses)
Rain shell June–November

Health and comfort

Insect repellent
Rehydration sachets, pain relief, motion-sickness tablets for the ferry
Prescriptions in labelled bottles
Small first-aid kit; blister plasters
Earplugs (March, or any resort with a nightly show)

Tech

Phone, power bank, charging cables
eSIM or local SIM if you are leaving the resort
Offline maps downloaded
Waterproof phone pouch for boats and cenotes

For kids

Rash guards, swim shirts, puddle-jumper
Kids' reef-safe sunscreen and repellent
Snacks for transfers; a tablet with downloads for the two-hour Tulum ride
Car seat, or confirm one with your private transfer

If you are still deciding what kind of trip this is, the planner will tell you which column of the table above is yours.